by K. Richard, Oct 29, 2029 in NoTricksZone
For years scientists have been using biomarker evidence (IP25, PIP25) to reconstruct the Arctic’s sea ice history. The evidence shows modern (20th-21st century) Arctic sea ice is at its greatest extent since the Holocene began.
Scientists (Wu et al., 2020) have determined that from about 14,000 to 8,000 years ago, when CO2 lingered near 250 ppm, the Beaufort Sea (Arctic) was “nearly ice free throughout the year” (<0.2 PIP25) and ~4°C warmer than today in winter.
With CO2 at ~400 ppm, this region is 70-100% ice-covered (>0.8 PIP25) for all but 1-2 summer months in the modern (1988-2007) era.